


let your colours bleed (and blend with mine)

by karasunotsubasa



Category: Haikyuu!!
Genre: 3rd year 1st years, Aged-Up Character(s), Alternate Universe, Alternate Universe - Soulmates, Established Relationship, Fluff, Fluff and Hurt/Comfort, Kagehina Exchange 2015, M/M, Multiple Soulmates, Soul Bond, Soulmates, combined with a bit of original soulmate au, glowing chest at first touch au, relationship doubts
Language: English
Status: Completed
Published: 2015-12-22
Updated: 2015-12-22
Packaged: 2018-05-08 07:36:30
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,588
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5488997
Author URL: https://archiveofourown.org/users/karasunotsubasa/pseuds/karasunotsubasa
Summary: <blockquote class="userstuff">
              <p>His soul was red.</p>
            </blockquote>





	let your colours bleed (and blend with mine)

**Author's Note:**

> so it's that time of the year again and it's kagehina exchange and here's my lil thing I've prepared 
> 
> for **no170**   
>  I'm sorry I couldn't do the thing you originally asked for, but I hope you like this fic as well! taking this chance, I'd like to wish you merry christmas and lots of wonderful presents and warm hugs in the next few days *sends lots of love* and a very happy new year!
> 
> it's also kags' bday today, so happy birthday volleyball nerd~
> 
> and just a tiny bit of explanation about the au:  
> \- it's based on the 'chest glowing red/blue at first touch' au, but it's upped to the first touch after you turn 18 so that everyone's of age when finding their soulmates  
> \- when the glowing starts and it pulses with the heartbeats for as long as 10 beats, where the amount of beats means how compatible the two people resonating are: under 5 is considered platonic and not worth exploring romantically, 6-7 is optimal for dating around in search for higher compatibility, 8-9 are what people usually settle for bc 10s are really rare and it could take long years to find a 10 so most ppl just go with 9s and 8s if they click; and then there are 10s which are perfect soulmates and are very rare to find  
> \- at first kiss after resonating a soul bond is formed and it can only be broken when either of the soulmates kiss someone of higher compatibility

His soul was red. The red of freshly picked raspberries his mom used to bring for him and Natsu to snack on when he was younger. It was the same red he had seen so many times in the mirror when his cheeks coloured in embarrassment, and the same red his eyes reflected in breathless awe at the dawn of the day when the summer sun dipped behind the horizon, painting the world in colour for the last time before it turned to darkness.

His soul was red, and every time the beat of it coursed through his body, excitement boiling hot in his veins, Shouyou was reminded that he was the warmth, the sun, the passion. His soulmate was somewhere out there, their soul a contrast to his own, completing him, contradicting him, perfecting him – a rich royal blue that reminded Shouyou so much of the knapweeds that grew in bunches in the small garden behind his house.

His soul was red, and pulsing fast in his chest, once, twice, thrice... and then it died down, red fading back to the yellow of his shirt and Shouyou's excitement vanished along with the last of its glow. Three beats only... He hid his disappointment behind a smile as he glanced up at Tsukishima, whose face was scrunched up in a frown.

It was a week after Tsukishima's eighteen birthday and completely on accident, while they were both reaching for water bottles in the middle of practice, their elbows brushed: skin cold with sweat, sliding over each other, bones bumping together awkwardly. Shouyou's bottle landed on the floor noisily, but no one noticed because all eyes turned to them as the flashing started. And just as soon as it had, it stopped, the three bright beats hanging like a stormy cloud in the tense air between them.

It was hard to decipher what Tsukishima was thinking, but then again, it was always like that. So instead of trying to fry his brain by wondering what exactly that crease between Tsukishima's eyebrows could possibly mean, or why were his golden eyes slightly widened as if in surprise, Shouyou decided to take the easier route and just... go with it.

"Aren't you relieved we're not meant to be together forever?" Shouyou teased, bending down to pick up his bottle and when he straightened up Tsukishima's eyes were already narrowed down on him, his face impassive as usual. All was good.

"Who'd even want to be with you, midget," Tsukishima snorted and Shouyou bristled at the insult to his height. With a crooked smirk, Tsukishima added before Shouyou could interrupt him, "Except the King, of course."

"Don't call me that," a voice behind Shouyou spoke up, and Shouyou startled. How did he manage to forget that Kageyama was right there?

As the two bickered above Shouyou's head, he stared at his bottle deep in thought. His fingers tightened when his stomach flipped uncomfortably. The facts were: 1) he was dating Kageyama, 2) he didn't know if Kageyama was his soulmate because Kageyama's birthday was still months away, 3) every time his soul flared he forgot all about Kageyama, which in turn made him feel incredibly guilty, as if he was leading him on. Which he wasn't. He genuinely cared about his boyfriend, but... a boyfriend wasn't a soulmate. And Shouyou couldn't deny the pull.

He grimaced, pulling off the cap and taking a few gulps of the water. He and Kageyama were good together. They've been dating ever since their second year and Shouyou wouldn't be surprised if Kageyama was in fact his soulmate. It was so easy to trust in that, so easy to trust in _Kageyama_. They understood each other without words, and as they grew even closer, that understanding deepened and changed into something else – love that brimmed with unconditional trust.

And just like that, with only a flash of blue at someone else's touch, Shouyou discarded that trust, that love. Guilt throbbed in his chest as his heart clenched painfully. He hated this. He hated himself. But there was really nothing he could do. He couldn't lie to his own feelings. He could only hope that when December comes, Kageyama's chest will light up in royal blue and their souls will pulse together a full, beautiful ten.

Feeling a little better, Shouyou set the bottle down on the bench and turned to his boyfriend.

"Let's go practice that new quick," he said and without waiting for a reply, pulled Kageyama along with him.

Their hands brushed together, and Shouyou felt Kageyama's fingers lock with his own, brief as a breeze. He looked up and found himself lost in Kageyama's dark, stormy eyes, not for the first time noticing how they gleamed like gems in the bright lights of the gym. Kageyama's face was still scrunched in a scowl, but soft lines of concern around his eyes made a smile tug at Shouyou's lips.

"Are you okay?" Kageyama asked, his voice quiet even though there was no one in vicinity that could have heard him.

For a second, Shouyou thought about it. Was he okay? Was he really okay?

He looked up at Kageyama with a small smile. "Yeah," he answered. "I'm fine."

And he was. Or... he would be. In December, when Kageyama's soul _will_ resonate with his own in perfect harmony.

 

* * *

 

It was December, Kageyama's birthday only two days away, and Shouyou was a literal nervous wreck. He was jumpy and fidgety even more than usual, irritating not only the people around him, but also himself. His stomach was more upset than he ever remembered, his palms always sweaty and knees trembling whenever he saw his boyfriend. It was easy to be confident when the whole thing was far in the future, it was easy to convince himself everything would be alright, but when the date was that close...

Shouyou swallowed harshly, taking a deep breath to calm his racing heart. It didn't help much, he could still feel the annoyingly fast pulsing of blood in his ears. One of his hands was rubbing small circles on his abdomen to soothe the rising ache, but it was no use. Two days, it was only two more days and then he'll know. But frankly... the closer to Kageyama's birthday, the more Shouyou became convinced that he didn't really want to know.

What if Kageyama wasn't the one? What if their compatibility wasn't high enough? What if their souls didn't resonate at all? What if... they... broke up...?

The questions bombarded his brain, making his head spin with all the negative outcomes, playing on Shouyou's fears. He bumped his forehead on the cold metal of his locker. It cleared his mind a bit, but the trembling of his heart didn't stop. With a heavy sigh, Shouyou finished changing, his hand briefly stopping to press against his chest, right where he knew his soul resided. If only he could be sure Kageyama was his 10...

But he wasn't. And it was putting more stress on him than he would've liked to admit. For a few days now Kageyama had been giving him strange looks, and if Shouyou wasn't so panicked about the whole matter, he would have noticed the pinched expression on his boyfriend's face every time the topic resurfaced. He was so focused on his own fears and concerns that he didn't spare a thought for Kageyama's own feelings. That, added to the doubts already forming in his mind, made Shouyou cringe.

These past few days he was a shitty boyfriend, and an even shittier soulmate. It wouldn't surprise him if Kageyama's soul just decided to pick someone else over him, because... who would want someone like him? A ball of nerves, all doubts and no optimism? He knew that Kageyama deserved better than that, someone fierce and strong like he was. And Shouyou wasn't... all that.

With a final sigh, Shouyou grabbed his bag and exited the clubroom. He met Kageyama at the bottom of the stairs and together, in silence, they walked down the hill. The air between them wasn't heavy per se, but Shouyou could feel the lingering stench of worry and expectation crawling on his skin. He wasn't sure if Kageyama felt it too, but then Kageyama glanced down at him, a crease between his eyebrows and a tiny crinkle at the base of his nose which Shouyou had come to find incredibly adorable. The slight up in his mood disappeared as soon as Kageyama opened his mouth, though.

"Are you okay?" Shouyou was really starting to hate that question and the gentle tone Kageyama was recently using when speaking to him. It wasn't right. It wasn't _them_. His lips thinned into a line.

"I just want this to be over," he said without looking at his boyfriend, who he knew was gazing at him with concern hidden in his stormy eyes.

"It's only two days," Kageyama replied and with a corner of his eye Shouyou caught him shrugging. "We can make it."

 _Can we?_ Shouyou wanted to ask, but decided against it. His heart gave a pained pang against his ribcage.

They walked in silence, the only sound was the ground of grovel under their feet. Shouyou's hands, usually so warm, now were stone cold, his palms clammy. He has been with Kageyama for almost two years, almost all of high school... and just like that, all of it could come to an end.

Swallowing harshly, Shouyou stopped in his tracks. His eyes glowing intensely in the late afternoon sun, he watched Kageyama turn to him with a confused frown on his face. He caught the gaze of his stormy eyes and then took a step closer, locking his fingers around Kageyama's slim wrist. The skin was ice-cold to the touch and Shouyou's stomach knotted tighter with nerves.

"What if we're not–" his voice caught in his throat and he had to take a breath before he could speak again. "What if we're not compatible? What if we aren't... soulmates?" he finished in a whisper that betrayed all his fears.

Kageyama looked down at him, his brows knitted together. Shouyou didn't want to think about what it would be like without Kageyama in his life, but... If it happened...

"Do you trust me?" Kageyama asked and Shouyou startled at the out-of-the-blue question.

"Of course I do!" His fingers on Kageyama's wrist tightened. "You know that."

For a brief moment they stood there just looking at each other. Shouyou had no idea what Kageyama was thinking, but then the dark blue eyes softened and Kageyama smiled. A small, private smile, one that Shouyou knew was meant only for him.

"Then believe in me," Kageyama said, and with widened eyes, heart fluttering in his chest and breath stuck in his throat– Shouyou did.

 

* * *

 

There was no chaotic racing to the gym on the day of December 22nd. No shouting, no arguing. Just a nervous sort of tension in the air as they stood face to face before the heavy metal door. They looked at each other in silence, Shouyou's heart hammering in his chest loud enough that he was pretty sure Kageyama could hear it. There was a slight morning breeze tugging at their clothes, and yet Shouyou felt breathless as he looked into Kageyama's blue eyes. He would have probably stood there longer, paralyzed by fear and expectation, but then Kageyama was stretching out his hand, palm up and open, offering it for Shouyou to grasp.

So with heart in his throat, nauseous and sweaty, Shouyou let his own hand slid into Kageyama's.

Red light burst out of his chest and relief washed over him so strongly he felt his knees tremble. His fingers tightened around Kageyama's and he felt the familiar calluses of the setter's hand settle some of his nerves. By sheer force of will, Shouyou kept himself standing, watching the royal blue glow of Kageyama's chest pulse along with their joined heartbeats. He counted the beats, his lips moving soundlessly as he breathed the numbers away.

_One, two, three..._

He licked his lips that were suddenly too dry, his eyes briefly meeting Kageyama's. The dark blue that usually met his gaze was gone, though. The brightness of his soul seemed to have soaked into Kageyama's irises, making them shine like sapphires in the sun: crystal clear, expressive and _blue_.

_Four, five, six..._

Shouyou's fingers tightened further on Kageyama's hand. They slipped, his skin sweaty with nerves, with expectation. This was the moment they'll know, this was the time they'll see if they were truly meant to be. Shouyou's chest hurt from the way his heart hammered against his ribcage, but he didn't want to – _couldn't_ – break the moment. Kageyama's hand trembled slightly in his hold.

_Seven, eight..._

Black dots danced across his vision and Shouyou blinked them away, with a startle realizing he was holding his breath all this time. He inhaled shakily, his breath stuttering in his tightened throat. Even if this was it, even if they weren't a full ten, they could still be together, still be happy, still have a bright future...

_Nine..._

He was close to fainting when the glow of the ninth beat faded, but hope – strong, irresistible hope made him hold on to Kageyama's hand for dear life.

And then it happened: the tenth glow filled Shouyou's vision, it embedded itself in his eyes, imprinted in his mind, the sublime blend of red and blue.

Relief hit him suddenly and Shouyou felt his knees buckle underneath him, but Kageyama – oh his Kageyama, his mate, his _perfect ten_ – caught him before he could fall to the ground. Arm around the waist and chests aligned, he held Shouyou close as their hearts beat in unity.

"I told you," Kageyama said, his voice breathy with relief that he tried to hide, but which Shouyou could notice just as easily as the skip in his own heartbeat. "Believe in me."

A half-laugh, half-sob left Shouyou's mouth, his chest both light and heavy at the same time. Supporting himself on Kageyama's arms, he stood on his shaky legs. He bumped his forehead softly on Kageyama's chest, his face alight with a tender smile. He let his head rest against Kageyama for just a moment, closing his eyes briefly at the way his whole body resisted any intention of moving away. This was his place, after all, right there, by his _mate's_ side.

So Shouyou gave in to the pull and climbed to his tiptoes, angling his face up to find Kageyama's lips, letting his fingers curl in the material of Kageyama's collar, thumbing at the sensitive patch of skin on Kageyama's neck. They met in a slightly hesitant kiss, as if it was their first, as if they didn't know each other for years. But as soon as their chapped lips closed the distance, slanting together in a gentle caress, the light of their joined souls burst out brightly from their chests and all their awkwardness was gone. Warmth and acceptance took its place, and when they parted, Shouyou had trouble breathing through the happiness constricting his throat.

He did believe in Kageyama.

He always had and...

"I always will," Shouyou said, pulling Kageyama down for another kiss to which the other obliged with a steady hand at the back of Shouyou's neck and an arm around his waist that pulled him closer into Kageyama's chest.

A chest glowing with subtle royal blue that blended with Shouyou's red in perfect harmony.

**Author's Note:**

> so what do you think? ;3 I had many more ideas for this thing and I would have written some smut and more angst into it if my block didn't kick in orz   
> but I'm glad I finished this in time! maybe I'll write some more for this au one day hmmm


End file.
